It's "light rail" (really a streetcar line, and it has only five stations, from the Freighthouse Square transit center to downtown), has a security guard on every train.

It helps that almost nobody rides it, and that each train is a streetcar and thus a single car. The security guard spends most of his time kicking off homeless folk, because no fare is charged to ride the train (it was basically built as a way to placate the city of Tacoma for inclusion in Sound Transit, and serves no real purpose other than to connect a bunch of government institutions.)

From what I would guess it costs to clean off the litter and cigarette butts (from the non-smoking platforms), it might be money better spent to put some patrol folks on a platform or a train periodically.

And, does anyone know why there is always a security officer at the end of the Yellow/Green lines at PSU? It appears all they do is kick off the stragglers before the trains go around the corner with the "Out of Service" sign in the windows.